Hypodermic needles are used worldwide in the process of administering immunization drugs to children and to control influenza.
To test the effectiveness of the drug delivery system, a special gel is used to mimic the behavior of human skin. Here the jet first creates a hole on the surface of the gel, then, at a lower jet pressure, the drug is delivered into the skin. This gel simulation also reveals that there is no “splashback” from the injection, which is an important patient safety factor.
The hypodermic needles, though found to be painful, are still preferred by the medical and healthcare professional as these needles are easy to use and are reliable in administering the exact dosage. They let the user have control over the task of injecting the drug.
Researches are being done worldwide focusing on the area of injectors that can alleviate the pain that is always associated with their application. The journal, Optics Letters published by the Optic Society (OSA) throws light on the latest researches, discoveries, and advancements that are developed in the field of optics and photonics. Optics Letters has recently published a paper, “Er:YAG laser Pulse for Small-Dose Splashback-Free Microjet Transdermal Drug Delivery," presented by Jack Yoh, professor of mechanical and aerospace engineering at Seoul National University in South Korea. Yoh and his graduate students have developed a new device that uses laser-powered needles that are found to be pain-free in their application.
Though other researchers have also come out with pain-free injectors, Yoh said that they are “mechanically-driven” and they depend on piston-like tools in administering the drug through the skin. Their device, according to Yoh, is unique as it uses erbium-doped yttrium aluminum garnet or Er:YAG laser in jetting out microscopic jets of drugs deep into the skin without causing any pain.
The Er:YAG, laser has already been found to be effective by many dermatologists who use it in their aesthetic facial treatments. The novel injector found by Yoh and his team is a combination of a small adaptor to hold the liquid drug and a chamber for storing water that acts as a “driving liquid”, enabling ease-of-flow of injection. This uses a laser with a wavelength of 2,940 nm that is easily absorbed by water. A highly flexible membrane separates the liquid drug and water. Due to the impact of laser pressure that lasts only for about 250 millionths of a second, water produces a vapor bubble that in turn causes tensile strength on the membrane to ooze out a jet of drug without the chance of “splashing-back” of drug. The diameter of the jet is only 150 millionths of a meter or micrometers and is capable of penetrating into the “epidermal layer” that is free from nerve-endings, making the injecting application pain-free.
Yoh is now involved in the production of low-cost replaceable injectors for clinical use. He is hopeful that this Er:YAG, laser technology will be useful in the application of small doses of drugs at multiple sites, especially in mass vaccinations aimed at developing childhood immunization.